By the end of this year, the San Diego Convention Center will have brought nearly 560,000 out-of-towners to the city who are projected to spend more than $654 million on lodging, food, shopping and entertainment, the center predicts.

In a report released Thursday, the Convention Center Corp. says that the projected $1.6 billion in overall economic impact from convention business will outpace that of the last two year, a sign of a recovering visitor and meeting industry. In 2011, the estimated impact on the economy was $1.4 billion.

The corporation points out in its report that its continuing efforts to market the center to medical meetings, which are big money-makers for cities, will yield 18 such conventions this year valued at more than $426 million in regional economic impact.

In all, some 65 conventions will be headed to San Diego, the largest among them the perennially sold-out Comic-Con, expected to draw 126,000 attendees. Still other blockbuster meetings expected to generate many millions in spending are the International Association of Police Chiefs, the American Academy of Dermatologists and Digestive Disease Week, a gathering of experts in gastroenterology and related fields.

"As we look into 2012, conventions are beginning to come back in full force, and one indicator for us is we’re finding that a number of conventions, as it gets closer to their meetings, are booking more rooms because their attendance is growing," said Carol Wallace, president of the Convention Center Corp. "We’re also seeing a number of our corporate clients beginning to book further out or come back."

While the number of expected conventions and attendees will actually be fewer than in 2011, spending will be higher because hotel room rates have risen as the economy has improved, and the mix of events this year will draw heavier spenders staying for longer periods, center officials explained.

Wallace said she remains concerned that many large conventions beyond just Comic-Con will not return or book at all if a planned expansion of the center is not undertaken. The Biotechnology Industry Organization, for example, which is scheduled to come to San Diego in 2014, has told the center that it cannot continue to meet here without a much larger center.

City leaders and convention center officials have argued that without a $520 million expansion, San Diego will lose substantial business to rival cities with larger centers. The current plan for financing the project calls for a levy on hotel rooms of 1 percent to 3 percent.

San Diego economist Marney Cox worries that such a substantial investment, while it may well create more business for the region, will also generate largely low-paying jobs.

"Each of the employees in the general visitor industry is on the low end of the pay scale, and we're a high cost of living area, so 75 percent-plus of that work force probably doesn’t earn enough money to pay that entire cost of living.

"Somewhere along the line the public sector in the form of subsidies has to make up that difference."

Convention center officials say they are especially buoyed by next week's convention of more than 3,000 meeting planners who are responsible for booking most of the major convention business throughout the country.

Wallace noted that the last time the Professional Convention Management Association met in San Diego, in 1996, it was largely responsible for bringing to San Diego more than 640 pieces of convention business in the subsequent 15 years.

"We’re now looking for another significant push in business from this group," she said.